https://www.polygon.com/2018/4/19/17256942/overwatch-glitch-retribution-competitive-play

Overwatch’s current limited-time event, Retribution, adds a bunch of new AI-controlled enemies, like the Assassin, Sniper and Heavy Assault. Those new enemies are supposed to be restricted to the new arcade mode, but some players have found a way to bring them into competitive multiplayer, thanks to a new bug.

The clips we’ve seen so far on Twitch and YouTube via Reddit appear to all be from the Korean version of Overwatch, but whatever glitch or hack is responsible for this wizardry isn’t limited to just Retribution. Players have joined games as Uprising’s Null Sector bots and Junkrat’s RIP Tire — sans Junkrat — as well.